That is a very good question involving two important, but different, events.  We read in 1 Peter 1:3, “Blessed be the God and Father of our Lord Jesus Christ, which according to his abundant mercy hath begotten us again unto a lively hope by the RESURRECTION OF JESUS CHRIST FROM THE DEAD.”  The Greek word for resurrection is “anastasis” and it means: a standing up again; raised to life again; rise from the dead.  The Lord Jesus spoke of this in Matthew 16:21 which says, “From that time forth began Jesus to shew unto his disciples, how that he must go unto Jerusalem, and suffer many things of the elders and chief priests and scribes, and be killed, and be raised again the third day.”  The Lord told His disciples of how He would be killed and then be resurrected in three days. 

Romans 4:25 tells us, “(Christ) was delivered over because of our wrongdoings, and was raised because of our justification.” (NASB).  We learn that Christ died for our sins and was raised again (resurrected) because His death was successful in saving us from our sin debt.  He was “raised BECAUSE of our justification.”  The resurrection occurred three days after the Lord’s death. 

Where was the Lord during the time between His death and His resurrection?  Let’s consider His words to the repentant thief who hung on a cross beside Him.  Luke 23:43 says, “And Jesus said unto him, Verily I say unto thee, TO DAY THOU SHALT BE WITH ME IN PARADISE.”  A little later, Christ said to His Father, “Father, into thy hands I commend my spirit: and having said thus, he gave up the ghost.” (Luke 23:46).  The Lord Jesus’ spirit was in Paradise with His Father for three days, while His body lay in a tomb.  The resurrection was when the Lord’s spirit returned and was reunited with His body.  Three days after His death, on the first day of the week, Mary Magdalene and others went to the tomb of the Lord Jesus and was told by an angel, “He is not here: for he is risen, as he said. Come, see the place where the Lord lay.”  (Matthew 28:6).

After His resurrection, the Lord told Mary Magdalene, “Jesus saith unto her, Touch me not; for I AM NOT YET ASCENDED TO MY FATHER: but go to my brethren, and say unto them, I ascend unto my Father, and your Father; and to my God, and your God.” (John 20:17).  The Greek word for ascended is “anabaino” and means: to go up; arise; come up.  The ascension refers to the time when the Lord Jesus physically rose up through the sky into Heaven.  What did the Lord do between His resurrection and His ascension?  The Apostle Paul tells us in 1 Corinthians 15:3-8, “For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; And that he was buried, and that he rose again the third day according to the scriptures: And that he was seen of Cephas, then of the twelve: After that, he was seen of above five hundred brethren at once; of whom the greater part remain unto this present, but some are fallen asleep. After that, he was seen of James; then of all the apostles. And last of all he was seen of me also, as of one born out of due time.”  The Lord spent this time encouraging His followers and preparing them for His physical absence. 

Acts 1:2-3 says, “Until the day in which he was taken up, after that he through the Holy Ghost had given commandments unto the apostles whom he had chosen: To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them FORTY DAYS, and speaking of the things pertaining to the kingdom of God.”  For forty days, the Lord remained on the earth ministering to His followers.

The ascension of the Lord is described in Acts 1:9-11, “And when he had spoken these things, while they beheld, he was taken up; and a cloud received him out of their sight. And while they looked stedfastly toward heaven as he went up, behold, two men stood by them in white apparel; Which also said, Ye men of Galilee, why stand ye gazing up into heaven? this same Jesus, which is taken up from you into heaven, shall so come in like manner as ye have seen him go into heaven.” 

In view of the Lord’s death, burial, resurrection and ascension into Heaven, believers are exhorted in Colossians 3:1-3, “If ye then be risen with Christ, seek those things which are above, where Christ sitteth on the right hand of God. Set your affection on things above, not on things on the earth. For ye are dead, and your life is hid with Christ in God.”  (483.4)